Made available in DSpace on 2014-12-17T15:18:13Z (GMT). No. of bitstreams: 1 AntonioJMV.pdf: 40604 bytes, checksum: 837880de27f78652daed108818974b9f (MD5) Previous issue date: 2007-02-23 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The Anguiliformes is constituted by 15 families, 141 sorts and 737 species. In this group eight families possess at least one karyotyped species, where a prevalence of karyotypes with 2n=38 is evidenced chromosomes and high NF, apparently basal for the Anguiliformes. The only family who shows a different karyotypic pattern from the others is the Muraenidae family. In this, of the eight species already described, all of them present 2n=42 chromosomes. Despite the dimension of this Order, few species present karyotypics descriptions. In the present work, a species of Ophichthidae, Myrichthys ocellatus (2n=38, 8m+14sm+10st+6a, NF=70) and three species of Muraenidae, Enchelycore nigricans (2n=42, 6m+8sm+12st+16a, NF=68), Gymnothorax miliaris (2n=42, 14m+18sm+10st, NF=84), Gymnothorax vicinus (2n=42, 8m+6sm+28a, NF=56) and Muraena pavonina (2n=42, 6m+4sm+32a, NF=52), collected in the coast of the Rio Grande do Norte state, Saint Peter and Paul Rocks and in the coast of Bahia state were analyzed. Mitotics chromosomes had been gotten through mitotic stimulation with yeasts. Among the analyzed species, it is observed the presence of characteristic large metacentric chromosomic pairs (≅10?m). As for the structural standard, heterochromatics regions in these species in centromeric position of the majority of the chromosomic pairs and simple ribosomal sites had been evidenced. For the Ophichthidae family, the gotten data corroborate the hypothesis of karyotypic diversification mediated by the occurrence of pericentrics inversions and robertsonians rearrangements, while in the Muraenidae, the identification of larger chromosomic values (2n=42), suggests derived karyotypes, possibly caused by possible chromosomic fissions / Os Anguiliformes s?o constitu?dos por 15 fam?lias, 141 g?neros e 737 esp?cies. Neste grupo oito fam?lias possuem pelo menos uma esp?cie cariotipada, onde ? evidenciada uma preval?ncia de cari?tipos com 2n=38 cromossomos e NF elevados, aparentemente basal para os Anguiliformes. A ?nica fam?lia que exibe um padr?o cariot?pico diferente das demais ? a fam?lia Muraenidae. Nesta, das oito esp?cies j? descritas, todas apresentam 2n=42 cromossomos. Apesar da dimens?o desta Ordem, poucas esp?cies apresentam descri??es cariot?picas. No presente trabalho, uma esp?cie de Ophichthidae, Myrichthys ocellatus (2n=38; 8m+14sm+10st+6a; NF=70) e quatro esp?cies de Muraenidae, Enchelycore nigricans (2n=42; 6m+8sm+12st+16a; NF=68), Gymnothorax miliaris (2n=42; 14m+18sm+10st; NF=84), Gymnothorax vicinus (2n=42; 8m+6sm+28a; NF=56) e Muraena pavonina (2n=42; 6m+4sm+32a; NF=52), coletadas no litoral do Rio Grande do Norte, Arquip?lago de S?o Pedro e S?o Paulo e litoral da Bahia, foram analisadas. Cromossomos mit?ticos foram obtidos atrav?s de prepara??es de curto termo, precedidas por estimula??o mit?tica com levedura. Entre as esp?cies observa-se a presen?a de grandes pares cromoss?micos metac?ntricos (≅10?m) caracter?sticos. Quanto aos padr?es estruturais nestas esp?cies foram evidenciadas regi?es heterocrom?ticas em posi??o centrom?rica da maioria dos pares cromoss?micos e s?tios ribossomais simples. Para a fam?lia Ophichthidae, os dados obtidos corroboram a hip?tese de diversifica??o cariot?pica mediada pela ocorr?ncia de invers?es peric?ntricas e rearranjos robertsonianos, enquanto que nos Muraenidae, a identifica??o de valores cromoss?micos maiores (2n=42), sugere cari?tipos mais derivados, possivelmente ocasionados por poss?veis fiss?es cromoss?micas